A cellular wireless network typically includes a number of base stations that are configured to provide wireless coverage areas, such as cells and cell sectors, in which user equipment devices (UEs) such as cell phones, tablet computers, tracking devices, embedded wireless modules, and other wirelessly equipped communication devices (whether or not user operated), can operate. In turn, each base station could be coupled with network infrastructure that provides connectivity with one or more transport networks, such as the public switched telephone network (PSTN) and/or the Internet for instance. With this arrangement, a UE within coverage of the network could engage in air interface communication with a base station and could thereby communicate via the base station with various remote network entities or with other UEs served by the base station.
Such a network could operate in accordance with a particular air interface protocol (or radio access technology), with communications from the base stations to UEs defining a downlink or forward link and communications from the UEs to the base stations defining an uplink or reverse link. Examples of existing air interface protocols include, without limitation, Long Term Evolution (LTE) (using Orthogonal Frequency Division Multiple Access (OFDMA) and Single-Carrier Frequency Division Multiple Access (SC-FDMA)), Code Division Multiple Access (CDMA) (e.g., 1xRTT and 1xEV-DO), Global System for Mobile Communications (GSM), WI-FI, and BLUETOOTH, among other examples. Each protocol could define its own procedures for registration of UEs, initiation of communications, handoff between coverage areas, and other functions related to air interface communication.
In accordance with the air interface protocol, each coverage area could operate on one or more carrier frequencies and could define on each carrier a number of air interface channels for carrying information between the base station and UEs. These channels could be defined in various ways, such as through frequency division multiplexing, time division multiplexing, and/or code-division multiplexing for instance.
By way of example, on a given carrier frequency, a coverage area could be structured to define a pilot channel or reference channel on which the base station broadcasts a pilot signal or reference signal that UEs could detect as an indication of coverage and could measure to evaluate coverage strength. Further, the coverage area could define one or more uplink control channels on which UEs could transmit control messages such as access requests, registration requests, and scheduling requests to the base station. And the coverage area could define one or more downlink control channels on which the base station could transmit control messages such as scheduling directives, system information messages, and page messages to UEs. Each coverage area could then further define one or more traffic channels or other resource for carrying communication traffic such as voice data and other data between the base station and served UEs.
In some arrangements, when a UE first powers on or enters into coverage of the network, the UE could scan for and identify a strongest pilot or reference signal and could register with the network by transmitting a registration request or attach request to a base station providing that signal. This registration process could serve to notify the network of UE's presence in a particular coverage area and could facilitate network authentication of the UE. Once registered, the UE could then operate in an idle mode in which the UE has no assigned traffic channel resources on which to engage in bearer communication but the UE monitors a downlink control channel to receive overhead information and to check for any page messages.
When the network has a communication (such as a voice call or other traffic) to provide to a UE that is registered with the network but is operating in the idle mode, the network could page the UE in an effort to then facilitate assigning traffic channel resources to the UE. In particular, the network could transmit on the downlink a page message addressed to the UE. Assuming the UE receives this page message, the UE could then transmit to the network a page response message on the uplink. And upon receipt of the page response message, the network could then assign traffic channel resources to the UE, for use to carry the communication, thus transitioning the UE to a connected or active mode in which the UE could engage in the communication.
Likewise, when an idle UE seeks to initiate (originate) a communication, such as to place a voice call or engage in other bearer communication, the UE could transmit on the uplink to the base station an origination or connection request, and the network could then assign traffic channel resources to the UE for use to carry the communication, similarly transitioning the UE to a connected or active mode in which the UE can engage in the communication.